@article{DAN_1989_305_2_a7,
     author = {P. L. Ul'yanov},
     title = {Classes of infinitely differentiable functions},
     journal = {Doklady Akademii Nauk},
     pages = {287--290},
     publisher = {mathdoc},
     volume = {305},
     number = {2},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_305_2_a7/}
}